1. Field of the Invention
The present invention relates generally to a liquid oxygen manifold, and more particularly to a manifold for use with a liquid oxygen storage/delivery apparatus.
2. Description of the Background Art
Therapeutic oxygen is the delivery of relatively pure oxygen to a patient in order to ease pulmonary/respiratory problems. When a patient suffers from breathing problems, inhalation of oxygen may ensure that the patient is getting an adequate level of oxygen into his or her bloodstream.
Therapeutic oxygen may be warranted in cases where a patient suffers from a loss of lung capacity for some reason. Some medical conditions that may make oxygen necessary are chronic obstructive pulmonary disease (COPD) including asthma, emphysema, lung cancer, etc., as well as cystic fibrosis, lung injuries, and cardiovascular diseases, for example.
Related art practice has been to provide portable oxygen in two ways. In a first approach, compressed oxygen gas is provided in a pressure bottle, and the gas is output through a pressure regulator through a hose to the nostrils of the patient. The bottle is often wheeled so that the patient may be mobile. This is a fairly simple portable arrangement.
The drawback of compressed, gaseous oxygen is that a full charge of a bottle that is portable does not last a desirable amount of time. In order to get around this limitation, in a second approach a related art liquid oxygen (LOX) apparatus has been used wherein liquid oxygen is stored in a container and the gaseous oxygen that evaporates from the LOX is inhaled by the patient.
The LOX apparatus enjoys a longer usable charge than the compressed gas apparatus for a given size and weight, but has its own drawbacks. LOX, being a liquid that is very cold, requires a vacuum-insulated container.
The LOX in a storage container transforms from a liquid state to a gaseous state as it warms, with a resultant increase in internal gas pressure. Therefore, a LOX storage container typically contains both liquid and gaseous phases of oxygen.
FIG. 1 shows a related art LOX storage container 100, having an inner container 104 and an outer container 107. The two are usually separated by at least a partial vacuum to reduce heat transfer to the LOX. For input and output ports, the inner container 104 is formed with a neck that is inside a similar neck formed in the outer container 107. Input and output ports may include a liquid withdrawal port 112, a gas withdrawal vent port 111, and a gas vent port 110. One of these ports may also be a liquid fill port, or a separate liquid fill port may exist on the related art LOX storage container 100. As a result, the related art storage container 100 may suffer from unacceptable levels of heat transfer via conduction by the necks of the various ports of the inner storage container 104.
Use of related art storage container typically requires a gas vent tube, a gas withdrawal tube, and a liquid withdrawal tube. The multiple ports require multiple transition joints, and multiple attachments such as welds, resulting in multiple heat entry points and a greater reliability concern.
There remains a need in the art, therefore, for an improved LOX storage/delivery apparatus.
A manifold for a liquid oxygen (LOX) storage/delivery apparatus is provided according to the invention. The manifold for a liquid oxygen (LOX) storage/delivery apparatus comprises a gas conduit adapted to communicate with a source of gaseous oxygen, the gas conduit allowing passage of gaseous oxygen and containing a liquid oxygen conduit inside the gas conduit, with the liquid oxygen conduit passing through the manifold, a gas withdrawal conduit communicating with the gas conduit, and a gas vent conduit communicating with the gas conduit, wherein the manifold permits independent liquid oxygen passage, independent gaseous oxygen passage, and independent gaseous oxygen venting.
The above and other features and advantages of the present invention will be further understood from the following description of the preferred embodiment thereof, taken in conjunction with the accompanying drawings.